FlashAttention-2 release

csrc/flash_attn/src/flash_bwd_hdim192_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+template<>
+void run_mha_bwd_<cutlass::half_t, 192>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim192<cutlass::half_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim224_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+template<>
+void run_mha_bwd_<cutlass::bfloat16_t, 224>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim224<cutlass::bfloat16_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim224_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+template<>
+void run_mha_bwd_<cutlass::half_t, 224>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim224<cutlass::half_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim256_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+template<>
+void run_mha_bwd_<cutlass::bfloat16_t, 256>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim256<cutlass::bfloat16_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim256_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+template<>
+void run_mha_bwd_<cutlass::half_t, 256>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim256<cutlass::half_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim32_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+// template<>
+// void run_mha_bwd_<cutlass::bfloat16_t, 32>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+//     using elem_type = cutlass::bfloat16_t;
+//     run_flash_bwd<Flash_bwd_kernel_traits<32, 128, 128, 8, 4, 4, 4, false, false, elem_type>>(params, stream, configure);
+// }
+
+template<>
+void run_mha_bwd_<cutlass::bfloat16_t, 32>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim32<cutlass::bfloat16_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim32_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+// template<>
+// void run_mha_bwd_<cutlass::half_t, 32>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+//     using elem_type = cutlass::half_t;
+//     run_flash_bwd<Flash_bwd_kernel_traits<32, 128, 128, 8, 4, 4, 4, false, false, elem_type>>(params, stream, configure);
+// }
+
+template<>
+void run_mha_bwd_<cutlass::half_t, 32>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim32<cutlass::half_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim64_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+// template<>
+// void run_mha_bwd_<cutlass::bfloat16_t, 64>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+//     using elem_type = cutlass::bfloat16_t;
+//     run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 128, 8, 4, 4, 4, false, false, elem_type>>(params, stream, configure);
+// }
+
+template<>
+void run_mha_bwd_<cutlass::bfloat16_t, 64>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim64<cutlass::bfloat16_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim64_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+// template<>
+// void run_mha_bwd_<cutlass::half_t, 64>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+//     using elem_type = cutlass::half_t;
+//     // Changing AtomLayoutMdQ from 2 to 4 takes the same time
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 64, 128, 8, 2, 4, 2, false, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 64, 128, 8, 2, 4, 2, true, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 128, 8, 2, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     // This is slightly faster. We want to split M more so we need fewer registers to store LSE.
+//     run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 128, 8, 4, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 64, 8, 4, 2, 4, true, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 64, 64, 4, 2, 2, 2, true, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 32, 128, 4, 1, 4, 1, false, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 16, 128, 4, 1, 4, 1, false, false, elem_type>>(params, stream, configure);
+//     // M=128, N=64 is quite slow, I think because we need to read/write dQaccum twice as many times
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 64, 8, 2, 2, 2, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 64, 8, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 16, 256, 8, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 128, 8, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 64, 64, 4, false, elem_type>>(params, stream, configure);
+
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 256, 64, 8, 8, 4, 8, false, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 256, 64, 8, 8, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     // run_flash_bwd<Flash_bwd_kernel_traits<64, 128, 64, 4, 4, 2, 4, false, false, elem_type>>(params, stream, configure);
+// }
+
+template<>
+void run_mha_bwd_<cutlass::half_t, 64>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim64<cutlass::half_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim96_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+// template<>
+// void run_mha_bwd_<cutlass::bfloat16_t, 96>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+//     using elem_type = cutlass::bfloat16_t;
+//     if (params.h == params.h_k) {
+//         run_flash_bwd<Flash_bwd_kernel_traits<96, 64, 128, 8, 2, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     } else {
+//         run_flash_bwd_seqq_parallel<Flash_bwd_kernel_traits<96, 128, 64, 8, 4, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     }
+// }
+
+template<>
+void run_mha_bwd_<cutlass::bfloat16_t, 96>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim96<cutlass::bfloat16_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_bwd_hdim96_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_bwd_launch_template.h"
+
+// template<>
+// void run_mha_bwd_<cutlass::half_t, 96>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+//     using elem_type = cutlass::half_t;
+//     if (params.h == params.h_k) {
+//         // run_flash_bwd<Flash_bwd_kernel_traits<96, 64, 128, 8, 2, 4, 4, true, false, elem_type>>(params, stream, configure);
+//         // This is very slightly faster
+//         run_flash_bwd<Flash_bwd_kernel_traits<96, 64, 128, 8, 2, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     } else {
+//         run_flash_bwd_seqq_parallel<Flash_bwd_kernel_traits<96, 128, 64, 8, 4, 4, 4, false, false, elem_type>>(params, stream, configure);
+//     }
+// }
+
+template<>
+void run_mha_bwd_<cutlass::half_t, 96>(Flash_bwd_params &params, cudaStream_t stream, const bool configure) {
+    run_mha_bwd_hdim96<cutlass::half_t>(params, stream, configure);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_fwd_hdim128_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+// template<>
+// void run_mha_fwd_<cutlass::bfloat16_t, 128>(Flash_fwd_params &params, cudaStream_t stream) {
+//     using elem_type = cutlass::bfloat16_t;
+//     if (params.p_dropout == 1.f) {
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 64, 4, false, false, elem_type>, false>(params, stream);
+//     } else {
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 32, 4, false, false, elem_type>, true>(params, stream);
+//     }
+// }
+template<>
+void run_mha_fwd_<cutlass::bfloat16_t, 128>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim128<cutlass::bfloat16_t>(params, stream);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_fwd_hdim128_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+// template<>
+// void run_mha_fwd_<cutlass::half_t, 128>(Flash_fwd_params &params, cudaStream_t stream) {
+//     using elem_type = cutlass::half_t;
+//     if (params.p_dropout == 1.f) {
+//         // Using 8 warps (128 x 128 and 256 x 64) is 28% slower for seqlen=2k
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 64, 4, false, false, elem_type>, false>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 64, 4, true, false, elem_type>, false>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 64, 4, false, true, elem_type>, false>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 64, 4, true, true, elem_type>, false>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 32, 4, false, false, elem_type>, false>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 64, 64, 4, false, false, elem_type>, false>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 64, 128, 4, false, false, elem_type>, false>(params, stream);
+//         // 1st ones are good for H100, A100
+//         // 2nd one is good for A6000 bc we get slightly better occupancy
+//     } else {
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 32, 4, false, false, elem_type>, true>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 32, 4, true, false, elem_type>, true>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<128, 128, 32, 4, true, true, elem_type>, true>(params, stream);
+//         // 1st one is good for H100, A100, A6000
+//     }
+// }
+
+template<>
+void run_mha_fwd_<cutlass::half_t, 128>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim128<cutlass::half_t>(params, stream);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_fwd_hdim160_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+// template<>
+// void run_mha_fwd_<cutlass::bfloat16_t, 160>(Flash_fwd_params &params, cudaStream_t stream) {
+//     using elem_type = cutlass::bfloat16_t;
+//     BOOL_SWITCH(params.p_dropout < 1.f, Is_dropout, [&] {
+//         run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 32, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//     });
+// }
+template<>
+void run_mha_fwd_<cutlass::bfloat16_t, 160>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim160<cutlass::bfloat16_t>(params, stream);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_fwd_hdim160_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+// template<>
+// void run_mha_fwd_<cutlass::half_t, 160>(Flash_fwd_params &params, cudaStream_t stream) {
+//     using elem_type = cutlass::half_t;
+//     BOOL_SWITCH(params.p_dropout < 1.f, Is_dropout, [&] {
+//         run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 32, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 32, 4, false, true, elem_type>, Is_dropout>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 64, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<160, 64, 64, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 64, 4, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<160, 64, 128, 4, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<160, 64, 64, 4, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 64, 8, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<160, 128, 128, 8, false, elem_type>>(params, stream);
+//         // For A6000, no-causal, 1st is fastest. causal, 4th is fastest.
+//         // For A100, H100, 1st is fastest.
+//     });
+// }
+template<>
+void run_mha_fwd_<cutlass::half_t, 160>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim160<cutlass::half_t>(params, stream);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_fwd_hdim192_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+// template<>
+// void run_mha_fwd_<cutlass::bfloat16_t, 192>(Flash_fwd_params &params, cudaStream_t stream) {
+//     using elem_type = cutlass::bfloat16_t;
+//     BOOL_SWITCH(params.p_dropout < 1.f, Is_dropout, [&] {
+//         run_flash_fwd<Flash_fwd_kernel_traits<192, 64, 64, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//     });
+// }
+template<> void run_mha_fwd_<cutlass::bfloat16_t, 192>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim192<cutlass::bfloat16_t>(params, stream);
+}

csrc/flash_attn/src/flash_fwd_hdim192_fp16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+// template<>
+// void run_mha_fwd_<cutlass::half_t, 192>(Flash_fwd_params &params, cudaStream_t stream) {
+//     using elem_type = cutlass::half_t;
+//     BOOL_SWITCH(params.p_dropout < 1.f, Is_dropout, [&] {
+//         run_flash_fwd<Flash_fwd_kernel_traits<192, 64, 64, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<192, 128, 32, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//         run_flash_fwd<Flash_fwd_kernel_traits<192, 64, 32, 4, false, false, elem_type>, Is_dropout>(params, stream);
+//         // This one is slightly faster for causal?
+//         // run_flash_fwd<Flash_fwd_kernel_traits<192, 128, 64, 8, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<192, 128, 32, 4, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<192, 128, 64, 4, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<192, 64, 128, 4, false, elem_type>>(params, stream);
+//         // run_flash_fwd<Flash_fwd_kernel_traits<192, 128, 128, 8, false, elem_type>>(params, stream);
+//     });
+//     // For A100 H100, 1st is faster with dropout, 3rd is faster without dropout
+//     // For A6000, 1st is faster when causal, 3rd is faster when not causal
+// }
+template<>
+void run_mha_fwd_<cutlass::half_t, 192>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim192<cutlass::half_t>(params, stream);
+}
\ No newline at end of file

csrc/flash_attn/src/flash_fwd_hdim224_bf16_sm80.cu

+// Copyright (c) 2023, Tri Dao.
+
+// Splitting the different head dimensions to different files to speed up compilation.
+
+#include "flash_fwd_launch_template.h"
+
+template<> void run_mha_fwd_<cutlass::bfloat16_t, 224>(Flash_fwd_params &params, cudaStream_t stream) {
+    run_mha_fwd_hdim224<cutlass::bfloat16_t>(params, stream);
+}